let EventUtil = {
	addHandler: function(oElement, sEvent, fnHandler) {
		oElement.addEventListener ? oElement.addEventListener(sEvent, fnHandler, false) : oElement.attachEvent("on" +
			sEvent, fnHandler);
	},
	removeHandler: function(oElement, sEvent, fnHandler) {
		oElement.removeEventListener ? oElement.removeEventListener(sEvent, fnHandler, false) : oElement.detachEvent("on" +
			sEvent, fnHandler);
	},
	addLoadHandler: function(fnHandler) {
		this.addHandler(window, "load", fnHandler);
	}
}
$("#btn2").click(function() {
	$("#btn1").val("可以点击了");
	$("#btn1").bind("click", function() {
		alert("绑定点击事件");
	})
});
$("#btn3").click(function() {
	$("#btn1").val("毫无用处的按钮");
	$("#btn1").unbind()
});
